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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ba5d0181 SW |
2 | /* |
3 | * Driver for MediaTek SoC based RTC | |
4 | * | |
5 | * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com> | |
ba5d0181 SW |
6 | */ |
7 | ||
8 | #include <linux/clk.h> | |
9 | #include <linux/interrupt.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/of_address.h> | |
12 | #include <linux/of_device.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/rtc.h> | |
15 | ||
16 | #define MTK_RTC_DEV KBUILD_MODNAME | |
17 | ||
18 | #define MTK_RTC_PWRCHK1 0x4 | |
19 | #define RTC_PWRCHK1_MAGIC 0xc6 | |
20 | ||
21 | #define MTK_RTC_PWRCHK2 0x8 | |
22 | #define RTC_PWRCHK2_MAGIC 0x9a | |
23 | ||
24 | #define MTK_RTC_KEY 0xc | |
25 | #define RTC_KEY_MAGIC 0x59 | |
26 | ||
27 | #define MTK_RTC_PROT1 0x10 | |
28 | #define RTC_PROT1_MAGIC 0xa3 | |
29 | ||
30 | #define MTK_RTC_PROT2 0x14 | |
31 | #define RTC_PROT2_MAGIC 0x57 | |
32 | ||
33 | #define MTK_RTC_PROT3 0x18 | |
34 | #define RTC_PROT3_MAGIC 0x67 | |
35 | ||
36 | #define MTK_RTC_PROT4 0x1c | |
37 | #define RTC_PROT4_MAGIC 0xd2 | |
38 | ||
39 | #define MTK_RTC_CTL 0x20 | |
40 | #define RTC_RC_STOP BIT(0) | |
41 | ||
42 | #define MTK_RTC_DEBNCE 0x2c | |
43 | #define RTC_DEBNCE_MASK GENMASK(2, 0) | |
44 | ||
45 | #define MTK_RTC_INT 0x30 | |
46 | #define RTC_INT_AL_STA BIT(4) | |
47 | ||
48 | /* | |
49 | * Ranges from 0x40 to 0x78 provide RTC time setup for year, month, | |
50 | * day of month, day of week, hour, minute and second. | |
51 | */ | |
52 | #define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20)) | |
53 | ||
54 | #define MTK_RTC_AL_CTL 0x7c | |
55 | #define RTC_AL_EN BIT(0) | |
56 | #define RTC_AL_ALL GENMASK(7, 0) | |
57 | ||
58 | /* | |
59 | * The offset is used in the translation for the year between in struct | |
60 | * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA) | |
61 | */ | |
62 | #define MTK_RTC_TM_YR_OFFSET 100 | |
63 | ||
64 | /* | |
65 | * The lowest value for the valid tm_year. RTC hardware would take incorrectly | |
66 | * tm_year 100 as not a leap year and thus it is also required being excluded | |
67 | * from the valid options. | |
68 | */ | |
69 | #define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1) | |
70 | ||
71 | /* | |
72 | * The most year the RTC can hold is 99 and the next to 99 in year register | |
73 | * would be wraparound to 0, for MT7622. | |
74 | */ | |
75 | #define MTK_RTC_HW_YR_LIMIT 99 | |
76 | ||
77 | /* The highest value for the valid tm_year */ | |
78 | #define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT) | |
79 | ||
80 | /* Simple macro helps to check whether the hardware supports the tm_year */ | |
81 | #define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \ | |
82 | (_y) <= MTK_RTC_TM_YR_H) | |
83 | ||
84 | /* Types of the function the RTC provides are time counter and alarm. */ | |
85 | enum { | |
86 | MTK_TC, | |
87 | MTK_AL, | |
88 | }; | |
89 | ||
90 | /* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */ | |
91 | enum { | |
92 | MTK_YEA, | |
93 | MTK_MON, | |
94 | MTK_DOM, | |
95 | MTK_DOW, | |
96 | MTK_HOU, | |
97 | MTK_MIN, | |
98 | MTK_SEC | |
99 | }; | |
100 | ||
101 | struct mtk_rtc { | |
102 | struct rtc_device *rtc; | |
103 | void __iomem *base; | |
104 | int irq; | |
105 | struct clk *clk; | |
106 | }; | |
107 | ||
108 | static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val) | |
109 | { | |
110 | writel_relaxed(val, rtc->base + reg); | |
111 | } | |
112 | ||
113 | static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg) | |
114 | { | |
115 | return readl_relaxed(rtc->base + reg); | |
116 | } | |
117 | ||
118 | static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set) | |
119 | { | |
120 | u32 val; | |
121 | ||
122 | val = mtk_r32(rtc, reg); | |
123 | val &= ~mask; | |
124 | val |= set; | |
125 | mtk_w32(rtc, reg, val); | |
126 | } | |
127 | ||
128 | static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val) | |
129 | { | |
130 | mtk_rmw(rtc, reg, 0, val); | |
131 | } | |
132 | ||
133 | static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val) | |
134 | { | |
135 | mtk_rmw(rtc, reg, val, 0); | |
136 | } | |
137 | ||
138 | static void mtk_rtc_hw_init(struct mtk_rtc *hw) | |
139 | { | |
140 | /* The setup of the init sequence is for allowing RTC got to work */ | |
141 | mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC); | |
142 | mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC); | |
143 | mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC); | |
144 | mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC); | |
145 | mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC); | |
146 | mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC); | |
147 | mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC); | |
148 | mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0); | |
149 | mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); | |
150 | } | |
151 | ||
152 | static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, | |
153 | int time_alarm) | |
154 | { | |
155 | u32 year, mon, mday, wday, hour, min, sec; | |
156 | ||
157 | /* | |
158 | * Read again until the field of the second is not changed which | |
159 | * ensures all fields in the consistent state. Note that MTK_SEC must | |
160 | * be read first. In this way, it guarantees the others remain not | |
161 | * changed when the results for two MTK_SEC consecutive reads are same. | |
162 | */ | |
163 | do { | |
164 | sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)); | |
165 | min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN)); | |
166 | hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU)); | |
167 | wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW)); | |
168 | mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM)); | |
169 | mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON)); | |
170 | year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA)); | |
171 | } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC))); | |
172 | ||
173 | tm->tm_sec = sec; | |
174 | tm->tm_min = min; | |
175 | tm->tm_hour = hour; | |
176 | tm->tm_wday = wday; | |
177 | tm->tm_mday = mday; | |
178 | tm->tm_mon = mon - 1; | |
179 | ||
180 | /* Rebase to the absolute year which userspace queries */ | |
181 | tm->tm_year = year + MTK_RTC_TM_YR_OFFSET; | |
182 | } | |
183 | ||
184 | static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, | |
185 | int time_alarm) | |
186 | { | |
187 | u32 year; | |
188 | ||
189 | /* Rebase to the relative year which RTC hardware requires */ | |
190 | year = tm->tm_year - MTK_RTC_TM_YR_OFFSET; | |
191 | ||
192 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year); | |
193 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1); | |
194 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday); | |
195 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday); | |
196 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour); | |
197 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min); | |
198 | mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec); | |
199 | } | |
200 | ||
201 | static irqreturn_t mtk_rtc_alarmirq(int irq, void *id) | |
202 | { | |
203 | struct mtk_rtc *hw = (struct mtk_rtc *)id; | |
204 | u32 irq_sta; | |
205 | ||
206 | irq_sta = mtk_r32(hw, MTK_RTC_INT); | |
207 | if (irq_sta & RTC_INT_AL_STA) { | |
208 | /* Stop alarm also implicitly disables the alarm interrupt */ | |
209 | mtk_w32(hw, MTK_RTC_AL_CTL, 0); | |
210 | rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF); | |
211 | ||
212 | /* Ack alarm interrupt status */ | |
213 | mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA); | |
214 | return IRQ_HANDLED; | |
215 | } | |
216 | ||
217 | return IRQ_NONE; | |
218 | } | |
219 | ||
220 | static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm) | |
221 | { | |
222 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
223 | ||
224 | mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC); | |
225 | ||
22652ba7 | 226 | return 0; |
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227 | } |
228 | ||
229 | static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm) | |
230 | { | |
231 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
232 | ||
233 | if (!MTK_RTC_TM_YR_VALID(tm->tm_year)) | |
234 | return -EINVAL; | |
235 | ||
236 | /* Stop time counter before setting a new one*/ | |
237 | mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP); | |
238 | ||
239 | mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC); | |
240 | ||
241 | /* Restart the time counter */ | |
242 | mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
247 | static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm) | |
248 | { | |
249 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
250 | struct rtc_time *alrm_tm = &wkalrm->time; | |
251 | ||
252 | mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL); | |
253 | ||
254 | wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN); | |
255 | wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA); | |
256 | ||
257 | return 0; | |
258 | } | |
259 | ||
260 | static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm) | |
261 | { | |
262 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
263 | struct rtc_time *alrm_tm = &wkalrm->time; | |
264 | ||
265 | if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year)) | |
266 | return -EINVAL; | |
267 | ||
268 | /* | |
269 | * Stop the alarm also implicitly including disables interrupt before | |
270 | * setting a new one. | |
271 | */ | |
272 | mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN); | |
273 | ||
274 | /* | |
275 | * Avoid contention between mtk_rtc_setalarm and IRQ handler so that | |
276 | * disabling the interrupt and awaiting for pending IRQ handler to | |
277 | * complete. | |
278 | */ | |
279 | synchronize_irq(hw->irq); | |
280 | ||
281 | mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL); | |
282 | ||
283 | /* Restart the alarm with the new setup */ | |
284 | mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL); | |
285 | ||
286 | return 0; | |
287 | } | |
288 | ||
289 | static const struct rtc_class_ops mtk_rtc_ops = { | |
290 | .read_time = mtk_rtc_gettime, | |
291 | .set_time = mtk_rtc_settime, | |
292 | .read_alarm = mtk_rtc_getalarm, | |
293 | .set_alarm = mtk_rtc_setalarm, | |
294 | }; | |
295 | ||
296 | static const struct of_device_id mtk_rtc_match[] = { | |
297 | { .compatible = "mediatek,mt7622-rtc" }, | |
298 | { .compatible = "mediatek,soc-rtc" }, | |
299 | {}, | |
300 | }; | |
3fc990a5 | 301 | MODULE_DEVICE_TABLE(of, mtk_rtc_match); |
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302 | |
303 | static int mtk_rtc_probe(struct platform_device *pdev) | |
304 | { | |
305 | struct mtk_rtc *hw; | |
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306 | int ret; |
307 | ||
308 | hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL); | |
309 | if (!hw) | |
310 | return -ENOMEM; | |
311 | ||
312 | platform_set_drvdata(pdev, hw); | |
313 | ||
09ef18bc | 314 | hw->base = devm_platform_ioremap_resource(pdev, 0); |
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315 | if (IS_ERR(hw->base)) |
316 | return PTR_ERR(hw->base); | |
317 | ||
318 | hw->clk = devm_clk_get(&pdev->dev, "rtc"); | |
319 | if (IS_ERR(hw->clk)) { | |
320 | dev_err(&pdev->dev, "No clock\n"); | |
321 | return PTR_ERR(hw->clk); | |
322 | } | |
323 | ||
324 | ret = clk_prepare_enable(hw->clk); | |
325 | if (ret) | |
326 | return ret; | |
327 | ||
328 | hw->irq = platform_get_irq(pdev, 0); | |
329 | if (hw->irq < 0) { | |
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330 | ret = hw->irq; |
331 | goto err; | |
332 | } | |
333 | ||
334 | ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq, | |
335 | 0, dev_name(&pdev->dev), hw); | |
336 | if (ret) { | |
337 | dev_err(&pdev->dev, "Can't request IRQ\n"); | |
338 | goto err; | |
339 | } | |
340 | ||
341 | mtk_rtc_hw_init(hw); | |
342 | ||
343 | device_init_wakeup(&pdev->dev, true); | |
344 | ||
345 | hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, | |
346 | &mtk_rtc_ops, THIS_MODULE); | |
347 | if (IS_ERR(hw->rtc)) { | |
348 | ret = PTR_ERR(hw->rtc); | |
349 | dev_err(&pdev->dev, "Unable to register device\n"); | |
350 | goto err; | |
351 | } | |
352 | ||
353 | return 0; | |
354 | err: | |
355 | clk_disable_unprepare(hw->clk); | |
356 | ||
357 | return ret; | |
358 | } | |
359 | ||
ae0ac716 | 360 | static void mtk_rtc_remove(struct platform_device *pdev) |
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361 | { |
362 | struct mtk_rtc *hw = platform_get_drvdata(pdev); | |
363 | ||
364 | clk_disable_unprepare(hw->clk); | |
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365 | } |
366 | ||
367 | #ifdef CONFIG_PM_SLEEP | |
368 | static int mtk_rtc_suspend(struct device *dev) | |
369 | { | |
370 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
371 | ||
372 | if (device_may_wakeup(dev)) | |
373 | enable_irq_wake(hw->irq); | |
374 | ||
375 | return 0; | |
376 | } | |
377 | ||
378 | static int mtk_rtc_resume(struct device *dev) | |
379 | { | |
380 | struct mtk_rtc *hw = dev_get_drvdata(dev); | |
381 | ||
382 | if (device_may_wakeup(dev)) | |
383 | disable_irq_wake(hw->irq); | |
384 | ||
385 | return 0; | |
386 | } | |
387 | ||
388 | static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume); | |
389 | ||
390 | #define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops) | |
391 | #else /* CONFIG_PM */ | |
392 | #define MTK_RTC_PM_OPS NULL | |
393 | #endif /* CONFIG_PM */ | |
394 | ||
395 | static struct platform_driver mtk_rtc_driver = { | |
396 | .probe = mtk_rtc_probe, | |
ae0ac716 | 397 | .remove_new = mtk_rtc_remove, |
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398 | .driver = { |
399 | .name = MTK_RTC_DEV, | |
400 | .of_match_table = mtk_rtc_match, | |
401 | .pm = MTK_RTC_PM_OPS, | |
402 | }, | |
403 | }; | |
404 | ||
405 | module_platform_driver(mtk_rtc_driver); | |
406 | ||
407 | MODULE_DESCRIPTION("MediaTek SoC based RTC Driver"); | |
408 | MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>"); | |
409 | MODULE_LICENSE("GPL"); |